System and method for dual-coding for dual-hops channels

ABSTRACT

An origination device (e.g., a base station) encodes first and second data packets according to a first set of encoding parameters corresponding to channel conditions associated with a first communication link between a signal forwarding device and a destination device. The resulting first and second single-encoded data packets contain the same data. The origination device combines the first and second single-encoded data packets to generate a single-encoded data block. The origination device encodes the single-encoded data block, according to a second set of encoding parameters corresponding to channel conditions associated with a second communication link between the origination device and the signal forwarding device, to generate a dual-encoded data block. The dual-encoded data block is transmitted to the signal forwarding device.

CLAIM OF PRIORITY

The present application claims priority to Provisional Application No.

62/310,533, entitled “SYSTEM AND METHOD FOR DUAL-CODING FOR DUAL-HOPSCHANNELS,” filed Mar. 18, 2016, and to Provisional Application No.62/310,520, entitled “SYSTEM AND METHOD FOR DUAL-CODING TRANSMISSIONSFOR RELAYS,” filed Mar. 18, 2016, both assigned to the assignee hereofand hereby expressly incorporated by reference in their entirety.

FIELD

This invention generally relates to wireless communications and moreparticularly to dual-coding transmissions for dual-hops channels.

BACKGROUND

Some communication systems utilize a signal forwarding device, such as arepeater station, relay station or a self-backhauled station tofacilitate the transfer of information between user equipment (UE)devices and a core network. The signal forwarding device is typicallynot connected directly to the core network but still provides service tothe UE devices by forwarding information to and from the UE devices anda base station, which is connected to the core network. Where the signalforwarding device is a repeater, the repeater simply retransmitsdownlink signals received from another base station to the UE device andretransmits uplink signals received from the UE device to the other basestation. Although the repeater may apply limited signal processing tothe incoming signal such as filtering, frequency shifting, andamplification, a repeater will not decode the incoming signal that is tobe forwarded. Relay stations and self-backhaul stations perform at leastsome signal processing before retransmitting the information. Suchprocessing can vary from partial decoding to complete decoding of theincoming signal. For example, the incoming signal can be completelydecoded and used to generate a new signal or the incoming signal may notbe completely decoded but still used to transmit the forwarded outgoingsignal. Some of the various levels of processing (forwarding techniques)are sometimes referred to as amplify and forward (AF), partial decodingand forward (PDF), and decode and forward (DF) schemes.

SUMMARY

An origination device (e.g., a base station) encodes first and seconddata packets according to a first set of encoding parameterscorresponding to channel conditions associated with a firstcommunication link between a signal forwarding device and a destinationdevice. The resulting first and second single-encoded data packetscontain the same data. The origination device combines the first andsecond single-encoded data packets to generate a single-encoded datablock. The origination device encodes the single-encoded data block,according to a second set of encoding parameters corresponding tochannel conditions associated with a second communication link betweenthe origination device and the signal forwarding device, to generate adual-encoded data block. The dual-encoded data block is transmitted tothe signal forwarding device.

The signal forwarding device decodes the dual-encoded data block, usingdecoding parameters that correspond to the second set of encodingparameters, to obtain the first and second single-encoded data packets,which are encoded according to the first set of encoding parameters. Thesignal forwarding device transmits the first single-encoded data packetto the destination device. The destination device attempts to decode thefirst single-encoded data packet using decoding parameters thatcorrespond to the first set of encoding parameters. If the decoding issuccessful, the destination device will have successfully received thefirst single-encoded data packet. If the decoding is unsuccessful, thedestination device will transmit a request for retransmission to thesignal forwarding device. In response to the request for retransmission,the signal forwarding device transmits the second single-encoded datapacket to the destination device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram of an example of the circuitry utilizedwithin an origination device, a signal forwarding device, and adestination device to transmit dual-encoded data blocks.

FIG. 1B is a block diagram of an example of a wireless communicationsystem including an origination device, a signal forwarding device, anda destination device.

FIG. 2 is a flowchart of an example of a method of utilizing thewireless communication system of FIG. 1B to transmit dual-encoded data.

DETAILED DESCRIPTION

As discussed above, communication systems often employ repeaters, relaysand self-backhauled base stations to forward signals transmitted betweenbase stations and the UE devices served by the base stations. Signalsmay be forwarded from the base station to the UE device, from the UEdevice to the base station, or both. In some systems, scheduling ofcommunication resources for the communication channel between the signalforwarding device (e.g., repeater, relay, etc.) and the UE device isperformed by a scheduler at the base station or a central schedulerconnected to the base station. In the examples discussed herein, it isassumed that the scheduler is located at, or connected to, a basestation to/from which the signal forwarding device forwards signals.However, the scheduler may not be physically located at the base stationand may be located at any other suitable location (e.g., at the signalforwarding device or elsewhere in the radio access network to which thebase station belongs).

In a typical relay scenario, an anchor base station would onlysingle-encode data, which is intended for a destination device, usingencoding parameters that are appropriate for the channel conditionsbetween the base station and the relay node. Upon receipt of thetransmission from the base station, the relay node would decode the dataand subsequently encode the data using encoding parameters that areappropriate for the channel conditions between the relay and thedestination device (e.g., UE device). One drawback of such a scenario isthe additional processing delay experienced at the relay while the relayencodes the data before transmitting the data to the destination device.Another drawback of a typical relay scenario would be the delayexperienced when waiting for the origination device to retransmit a datapacket that was not successfully received by the destination device.However, for the examples discussed herein, various methods, devices,and systems will be described in which (1) an anchor base stationtransmits a dual-encoded data block that does not require any encodingby the signal forwarding device (e.g., relay), and (2) the relayreceives, for each data packet, an original packet and one or moreredundant encoded packets, from the base station so that the relay canretransmit a data packet that was not successfully received by thedestination device, without waiting for the base station to retransmitthe data packet.

Since the signal forwarding device is central to the examples, thenomenclature used throughout the description centers on the signalforwarding device. More specifically, an “origination device” is adevice from which a signal is transmitted to the signal forwardingdevice, and the signal being received at the signal forwarding devicefrom an origination device is referred to as a “received signal.”Similarly, a “destination device” is a device to which the signalforwarding device transmits a signal, which is referred to herein as a“forwarded signal.” Moreover, although most of the following examplesrefer to a base station as the “origination device” and to a UE deviceas the “destination device,” the examples may be modified so that the UEdevice is the “origination device,” and the base station is the“destination device.”

FIG. 1A is a block diagram of an example of the circuitry utilizedwithin an origination device, a signal forwarding device, and adestination device to transmit dual-encoded data. For example, thevarious blocks shown in FIG. 1A represent circuitry that is configuredto perform various functions and processes described herein. Althougheach function is shown as a separate box, the circuitry that actuallyperforms the recited functions for each box may be configured to performthe functions for multiple boxes. For example, a controller within theorigination device, the signal forwarding device, and/or the destinationdevice may be the circuitry that is configured to perform one or more ofthe functions shown in FIG. 1A.

The origination device 110 and destination device 114 may be any kind ofwireless communication devices and may be stationary or portable. Forthe examples discussed herein, the origination device 110 is a basestation, and the destination device 114 is a user equipment (UE) devicesuch as a handset. However, the devices 110, 114 may be different typesof devices in other circumstances. For example, both devices may be UEdevices. In some situations, the origination device, the signalforwarding device, and the destination device are all UE devices.

In the example of FIG. 1A, origination device 110 provides downlinkwireless communication service to destination device 114. Thus,destination device 114 receives downlink signals from origination device110, either directly or via signal forwarding device 138. In the exampleof FIG. 1A, origination device 110 transmits a dual-encoded data signalto signal forwarding device 138, and signal forwarding device 138forwards a single-encoded data signal to the destination device 114.

For example, origination device 110 either generates the user data 160or receives the user data 160 from another entity within the radioaccess network. In the example shown in FIG. 1A, the user data 160includes a first data packet and a second data packet, which containredundant data. Although only two data packets are shown in thisexample, additional redundant packets may be utilized. The originationdevice 110 has circuitry configured to add a first cyclic redundancycheck value (CRC 1) 162 to the user data 160. The CRC is anerror-detecting code that is used to detect if the received packet atthe receiver is in error or not. Although the examples shown hereinutilize CRC, any suitable error-detection techniques may be used.

After adding CRC 1, the user data 160 is encoded by Encoder 1, 164.Encoder 1 encodes the user data 160 according to a first set of encodingparameters corresponding to channel conditions associated with a firstcommunication link between the signal forwarding device 138 and thedestination device 114. The first set of encoding parameters comprises afirst encoding technique and/or a first encoding rate. The result ofencoding the user data 160 with Encoder 1 is a first single-encoded datapacket and a second single-encoded data packet.

In the example shown in FIG. 1A, combiner 165 combines the first andsecond single-encoded data packets, resulting in a single-encoded datablock.

However, any number of additional redundant data packets may be includedin the single-encoded data block, in other examples. Regardless of thenumber of data packets included in the single-encoded data block, thesingle-encoded data block, by itself, provides the needed redundancy forthe system to function properly. In other examples, however, theorigination device 110 may be configured such that the requiredredundancy may be achieved by utilizing multiple single-encoded datablocks that, either individually or collectively, provide the redundancyneeded for proper operation. This may include cases where the firstsingle-encoded data block does not have the same data as the secondsingle-encoded data block. In particular, for Hybrid Automatic RepeatRequest (HARQ) with partial retransmissions, the retransmitted block(i.e., the second single-encoded data block) may be smaller than thefirst transmission (i.e., the first single-encoded data block). In stillother cases, the combiner may be configured to not combine the firstsingle-encoded data block and the second single-encoded data block,which would allow the Decoder 2, 174, of the signal forwarding device138 to separately decode the first single-encoded data block and thesecond-encoded data block. Such a configuration would advantageouslyallow the signal forwarding device 138 to only decode the firstsingle-encoded data block prior to transmitting the first single-encodeddata block to the destination device 114. The signal forwarding device138 may then decode the second single-encoded data block aftertransmitting the first single-encoded data block to the destinationdevice 114. In this manner, the latency associated with decoding thesecond single-encoded data block (e.g., redundant data block), beforetransmitting the first single-encoded data block, is eliminated. Thus,any number and configuration of redundant data packets and/or datablocks may be utilized as long as the necessary redundancy is achieved.

A second CRC value (CRC 2) 166 is added to the single-encoded datablock.

Although a CRC is used for CRC 2, any suitable alternativeerror-detection technique may be used in place of CRC 2. Thesingle-encoded data block, along with CRC 2, is encoded by Encoder 2,168, which, in the example shown in FIG. 1A, utilizes a non-iterativetype encoding/decoding (e.g., Reed-Solomon Codes) to ensure low-latencyprocessing at the signal forwarding device 138. Encoder 2 encodes thesingle-encoded data block according to a second set of encodingparameters corresponding to channel conditions associated with a secondcommunication link between the origination device 110 and the signalforwarding device 138. The second set of encoding parameters comprises asecond encoding technique and/or a second encoding rate. The result ofencoding the single-encoded data block with Encoder 2 is a dual-encodeddata block.

One of the advantages of dual-encoding the data is that the encodingparameters selected for each stage of encoding can be selected based onthe channel conditions for a particular communication link. For example,Encoder 1 may encode the user data according to a first encodingtechnique that is better suited for transmissions between a signalforwarding device and a destination device (e.g., mobile UE device), andEncoder 2 may encode the single-encoded data block according to a secondencoding technique that is better suited for transmissions between anorigination device (e.g., base station) and a signal forwarding device.For example, the first encoding technique may be a convolutional coding,which is better suited for transmissions between a signal forwardingdevice and a destination device, and the second encoding technique maybe a turbo coding or rate-less channel coding using the Low DensityParity Codes (LDPC), which is better suited for transmissions between anorigination device and a signal forwarding device. However, any of thechannel coding techniques may be used for the originationdevice-to-signal forwarding device channel or the signal forwardingdevice-to-destination device channel.

Similarly, Encoder 1 may encode the user data at a first coding ratethat is better suited for transmissions between a signal forwardingdevice and a destination device (e.g., mobile UE device), and Encoder 2may encode the single-encoded data block at a second coding rate that isbetter suited for transmissions between an origination device (e.g.,base station) and a signal forwarding device. More specifically, theuser data may be encoded at a 1/3 coding rate to obtain the first andsecond single-encoded data packets, and the single-encoded data blockmay be encoded at a 2/3 coding rate to obtain the dual-encoded datablock, for example.

Regardless of the particular encoding parameters used, the dual-encodeddata block is modulated by modulator 170 of origination device 110. Inthe example shown in FIG. 1A, Quadrature Amplitude Modulation (QAM) isused. However, any other suitable modulation scheme may be used.Moreover, the modulation scheme utilized by modulator 170 may also beselected based on the channel conditions between the origination device110 and the signal forwarding device 138. The modulation of thedual-encoded data block yields a dual-encoded received signal 136.

Origination device 110 utilizes transmitter 122 to transmit thedual-encoded received signal 136 to signal forwarding device 138, whichreceives the transmission via receiver 142. The demodulator 172 ofsignal forwarding device 138 demodulates the dual-encoded receivedsignal 136 using a demodulation scheme that corresponds to themodulation scheme utilized by modulator 170. The demodulation of thedual-encoded received signal 136 yields the dual-encoded data block.

The Decoder 2, 174, decodes the dual-encoded data block, using decodingparameters that correspond to the second set of encoding parameters,which were used by Encoder 2, 168, of the origination device 110 toencode the single-encoded data block. The result of decoding thedual-encoded data block with Decoder 2 is the single-encoded data blockthat is encoded according to the first set of encoding parameters.Alternatively, as described above, if the combiner 165 is configured tonot combine the first and second single-encoded data blocks, the Decoder2 will yield two single-encoded data blocks that are encoded accordingto the first set of encoding parameters. However, the secondsingle-encoded data block does not need to be decoded at the same timeas the first single-encoded data block. Rather, the secondsingle-encoded data block can be decoded after the signal forwardingdevice 138 decodes and transmits the first single-encoded data block tothe destination device 114.

After decoding, the second CRC value (CRC 2), which was added to thesingle-encoded data block by the origination device 110, is checked byCRC 2 Check 176, which detects whether any errors are present in thesingle-encoded data block after decoding. If the CRC 2 Check 176 detectsan error, signal forwarding device 138 can send a negativeacknowledgment response (NACK) to the origination device 110, indicatingthat the dual-encoded received signal 136 was not successfully received.If the CRC 2 Check 176 does not detect an error, signal forwardingdevice 138 can send a positive acknowledgment response (ACK) to theorigination device 110, indicating that the dual-encoded received signal136 was successfully received.

If there are no errors, signal forwarding device 138 extracts the firstsingle-encoded data packet from the single-encoded data block and storesthe second single-encoded data packet in a memory (not shown) of thesignal forwarding device 138. Modulator 178 of signal forwarding device138 modulates the first single-encoded data packet. In the example shownin FIG. 1A, Quadrature Amplitude Modulation (QAM) is used by modulator178. However, any other suitable modulation scheme may be used.Moreover, the modulation scheme utilized by modulator 178 may also beselected based on the channel conditions between the signal forwardingdevice 138 and the destination device 114. The modulation of the firstsingle-encoded data packet yields a single-encoded forwarded signal 148.

Signal forwarding device 138 utilizes transmitter 146 to transmit thesingle-encoded forwarded signal 148 to destination device 114, whichreceives the transmission via receiver 130. The demodulator 180 ofdestination device 114 demodulates the single-encoded forwarded signal148 using a demodulation scheme that corresponds to the modulationscheme utilized by modulator 178. The demodulation of the single-encodedforwarded signal 148 yields the first single-encoded data packet.

The Decoder 1, 182, decodes the first single-encoded data packet, usingdecoding parameters that correspond to the first set of encodingparameters, which were used by Encoder 1, 164, of the origination device110 to encode the user data.

The result of decoding the first single-encoded data packet with Decoder1 is the user data. After decoding, the first CRC value (CRC 1), whichwas added to the user data by the origination device 110, is checked byCRC 1 Check 184, which detects whether any errors are present in theuser data after decoding.

If the CRC 1 Check 184 does not detect an error, destination device 114can send a positive acknowledgment response (ACK) to the signalforwarding device 138 and/or the origination device 110, indicating thatthe single-encoded forwarded signal 148 was successfully received. Ifthe destination device 114 sends an ACK to the origination device 110,the ACK can be sent either directly to the origination device 110 or tothe origination device 110 via signal forwarding device 138. If thereare no errors detected by CRC 1 Check 184, destination device 114 hassuccessfully received and decoded the user data (e.g., received userdata 186). If the ACK is sent directly to the origination device 110,the origination device 110 may inform the signal forwarding device 138that the second single-encoded data packet that is stored in memory maybe discarded.

Thus, by dual-encoding the user data at origination device 110 withfirst and second sets of encoding parameters that are selected based onthe channel conditions associated with (1) the communication linkbetween the signal forwarding device 138 and the destination device 114,and (2) the communication link between the origination device 110 andthe signal forwarding device 138, respectively, a more robust datadelivery system is created.

However, if the CRC 1 Check 184 detects an error, destination device 114sends a negative acknowledgment response (NACK) to the signal forwardingdevice 138, indicating that the single-encoded forwarded signal 148 wasnot successfully received. The NACK is considered, for this example, tobe a request for retransmission. Instead of forwarding the NACK to theorigination device 110, the signal forwarding device 138 retrieves thesecond single-encoded data packet that was previously stored in thememory of the signal forwarding device 138. If, however the NACK is sentdirectly to the origination device 110 by the destination device 114instead of to the signal forwarding device 138, the origination device110 may inform the signal forwarding device 138 that the firstsingle-encoded data packet was not successfully received at thedestination device 114.

Regardless of how the NACK is received at the signal forwarding device138, once the NACK is received, the modulator 178 of signal forwardingdevice 138 modulates the second single-encoded data packet, whichresults in another single-encoded forwarded signal 148. As before,signal forwarding device 138 utilizes transmitter 146 to transmit thesingle-encoded forwarded signal 148, which now contains the secondsingle-encoded data packet, to destination device 114, which receives,demodulates, decodes, and checks the single-encoded forwarded signal148, as described above. In other examples, a timer may be configuredsuch that if the signal forwarding device 138 fails to receive either anACK or a NACK from the destination device 114 within a predeterminedperiod of time after transmitting the first single-encoded data packet,then the signal forwarding device 138 will transmit the previouslystored second single-encoded data packet to the destination device 114.

If the reception of the second single-encoded data packet wassuccessful, the destination device 114 now has possession of the userdata in a more efficient and timely manner than would be the case in atypical relay scenario. For example, in a typical relay scenario, therewould be an additional delay while the signal forwarding device 138forwards the NACK from the destination device 114 to the originationdevice 110 and while the origination device 110 retransmits the data tothe signal forwarding device 138. However, since the signal forwardingdevice 138 of FIG. 1A already has the second single-encoded data packet,the signal forwarding device 138 can simply send the requestedretransmission without the additional latency experienced in a typicalrelay scenario.

If the destination device 114 is unable to successfully receive both thefirst and second single-encoded data packets, the destination device 114can transmit a NACK to the signal forwarding device 138 and/or theorigination device 110. In one example, the signal forwarding device 138modifies one or more of the modulation, encoding technique, encodingrate, and transmission power before retransmitting either the first orsecond single-encoded data packet to improve the likelihood of asuccessful retransmission to the destination device 114. Suchmodifications may be based on the channel conditions between the signalforwarding device 138 and the destination device 114. Alternatively, thesignal forwarding device 138 may forward the NACK for the secondsingle-encoded data packet to the origination device 110. In this case,the origination device 110 may regenerate the dual-encoded receivedsignal 136. In regenerating the dual-encoded received signal 136, theorigination device 110 may alter one or more of the modulation, encodingtechnique, encoding rate, and transmission power utilized by modulator170, Encoder 1, Encoder 2, and transmitter 122 before retransmitting thedual-encoded received signal 136 to improve the likelihood of asuccessful retransmission to the signal forwarding device 138 and to thedestination device 114.

In the other examples described above that utilize more than tworedundant data packets in a single data block or that utilize multipledata blocks to create the required redundancy, the only requirement forthe proper functioning of the methods described herein is that the datathat is being requested by the destination device 114 for retransmissionhas already been successfully received and stored by the signalforwarding device 138. Thus, the redundant data (e.g., secondsingle-encoded data packet) being requested for retransmission may havebeen included in the same data block or in a different data block thanthe data block that contained the first single-encoded data packet.

Moreover, although the technique discussed above in connection with FIG.1A presumes that the signal forwarding device 138 transmits the secondsingle-encoded data packet using the same modulation, encodingtechnique, encoding rate, and transmission power as the firstsingle-encoded data packet, the system may be modified so that one ormore of the modulation, encoding technique, encoding rate, andtransmission power may be altered to improve the likelihood of asuccessful transmission of the second single-encoded data packet to thedestination device 114. As described below, the modifications to thetransmission parameters for such a retransmission may be based onfeedback received regarding the channel conditions between the signalforwarding device 138 and the destination device 114.

FIG. 1B is a block diagram of an example of a wireless communicationsystem 100 including an origination device, a signal forwarding device,and a destination device. The origination device 110 and destinationdevice 114 may be any kind of wireless communication devices and may bestationary or portable. For the examples discussed herein, theorigination device 110 is a base station, and the destination device 114is a user equipment (UE) device such as a handset. However, the devices110, 114 may be different types of devices in other circumstances. Forexample, both devices may be UE devices. In some situations, theorigination device, the signal forwarding device, and the destinationdevice are all UE devices.

In the example of FIG. 1B, origination device 110 provides downlinkwireless communication service to destination device 114. Thus,destination device 114 receives downlink signals (not shown) fromorigination device 110, either directly or via signal forwarding device138. The downlink signals are received at the destination device 114through antenna 124 and receiver 130. Destination device 114 furthercomprises a controller 128 and a transmitter 126. Origination device 110transmits the downlink signals to destination device 114 and to signalforwarding device 138 via antenna 116 and transmitter 122.

Origination device 110 further comprises controller 120 and transmitter122, as well as other electronics, hardware, and code. The originationdevice 110 is any fixed, mobile, or portable equipment that performs thefunctions described herein. The various functions and operations of theblocks described with reference to the origination device 110 may beimplemented in any number of devices, circuits, or elements. Two or moreof the functional blocks may be integrated in a single device, and thefunctions described as performed in any single device may be implementedover several devices.

For the example shown in FIG. 1B, the origination device 110 may be afixed device or apparatus that is installed at a particular location atthe time of system deployment. Examples of such equipment include fixedbase stations or fixed transceiver stations. In some situations, theorigination device 110 may be mobile equipment that is temporarilyinstalled at a particular location. Some examples of such equipmentinclude mobile transceiver stations that may include power generatingequipment such as electric generators, solar panels, and/or batteries.Larger and heavier versions of such equipment may be transported bytrailer. In still other situations, the origination device 110 may be aportable device that is not fixed to any particular location.Accordingly, the origination device 110 may be a portable user devicesuch as a UE device in some circumstances.

The controller 120 includes any combination of hardware, software,and/or firmware for executing the functions described herein as well asfacilitating the overall functionality of the origination device 110. Anexample of a suitable controller 120 includes code running on amicroprocessor or processor arrangement connected to memory. Thetransmitter 122 includes electronics configured to transmit wirelesssignals. In some situations, the transmitter 122 may include multipletransmitters. The receiver 118 includes electronics configured toreceive wireless signals. In some situations, the receiver 118 mayinclude multiple receivers. The receiver 118 and transmitter 122 receiveand transmit signals, respectively, through an antenna 116. The antenna116 may include separate transmit and receive antennas. In somecircumstances, the antenna 116 may include multiple transmit and receiveantennas.

The transmitter 122 and receiver 118 in the example of FIG. 1B performradio frequency (RF) processing including modulation and demodulation.The receiver 118, therefore, may include components such as low noiseamplifiers (LNAs) and filters. The transmitter 122 may include filtersand amplifiers. Other components may include isolators, matchingcircuits, and other RF components. These components in combination orcooperation with other components perform the origination devicefunctions. The required components may depend on the particularfunctionality required by the origination device.

The transmitter 122 includes modulator 170 (shown in FIG. 1A), and thereceiver 118 includes a demodulator (not shown). The modulator 170modulates the signals to be transmitted as part of the dual-encodedreceived signal 136 and can apply any one of a plurality of modulationorders. The demodulator demodulates any signals received at theorigination device 110 in accordance with one of a plurality ofmodulation orders.

Scheduler 132 is located at origination device 110 in the example shownin FIG. 1B. However, the system 100 could be modified so that thescheduler 132 is located at any other suitable location. Regardless ofthe location of scheduler 132, the system 100 may be configured so thatmultiple entities within the radio access network (e.g., differentorigination devices, different signal forwarding devices, and differentdestination devices) can access the scheduler 132. For example, in anad-hoc topology, a first origination device can access the scheduler 132and transmit a dual-encoded received signal to the signal forwardingdevice at a given time, but a second origination device can access thescheduler 132 and transmit a dual-encoded received signal to the signalforwarding device at a second, different time.

The scheduler may be an application running on equipment connecteddirectly to origination device 110 or connected through a backhaul orother communication link. Regardless of the location of scheduler 132,channel quality information (CQI) 134 regarding the variouscommunication links within the system 100 is provided to scheduler 132,which uses the CQI 134 to schedule communication resources to be used bythe various entities within the system 100. For the example shown inFIG. 1B, the scheduler 132 utilizes CQI pertaining to the communicationlink between the origination device 110 and the destination device 114,CQI pertaining to the communication link between the origination device110 and the signal forwarding device 138, and CQI pertaining to thecommunication link between the signal forwarding device 138 and thedestination device 114. Based on the channel quality for at least one ofthese three communication links, the scheduler 132 schedulescommunication resources.

As discussed above, origination device 110 of FIG. 1B transmits adual-encoded received signal 136 (e.g. a downlink signal) to the signalforwarding device 138, which receives the dual-encoded received signal136 via antenna 140 and receiver 142. The signal forwarding device 138further comprises controller 144 and transmitter 146, as well as otherelectronics, hardware, and code. The signal forwarding device 138 is anyfixed, mobile, or portable equipment that performs the functionsdescribed herein. The various functions and operations of the blocksdescribed with reference to the signal forwarding device 138 may beimplemented in any number of devices, circuits, or elements. Two or moreof the functional blocks may be integrated in a single device, and thefunctions described as performed in any single device may be implementedover several devices.

For the example shown in FIG. 1B, the signal forwarding device 138 maybe a fixed device or apparatus that is installed at a particularlocation at the time of system deployment. Examples of such equipmentinclude fixed base stations or fixed transceiver stations. In somesituations, the signal forwarding device 138 may be mobile equipmentthat is temporarily installed at a particular location. Some examples ofsuch equipment include mobile transceiver stations that may includepower generating equipment such as electric generators, solar panels,and/or batteries. Larger and heavier versions of such equipment may betransported by trailer.

In still other situations, the signal forwarding device 138 may be aportable device that is not fixed to any particular location.Accordingly, the signal forwarding device 138 may be a portable userdevice such as a UE device in some circumstances.

In some implementations, the signal forwarding device 138 may be a basestation, eNB, or access point that performs signal forwarding functionsin addition to serving UE devices. For example, a self-backhauled eNB,connected to an anchor eNB, may be configured to perform signalforwarding functions for some UE devices in addition to directly servingother UE devices utilizing the wireless backhaul to the originationdevice 110 (e.g., anchor eNB). In other implementations, the signalforwarding device 138 may be a drone with cellular capability. Such adrone can easily move about towards locations where the existingcoverage from fixed base stations is lacking.

The controller 144 includes any combination of hardware, software,and/or firmware for executing the functions described herein as well asfacilitating the overall functionality of the signal forwarding device138. An example of a suitable controller 144 includes code running on amicroprocessor or processor arrangement connected to memory. Thetransmitter 146 includes electronics configured to transmit wirelesssignals. In some situations, the transmitter 146 may include multipletransmitters. The receiver 142 includes electronics configured toreceive wireless signals. In some situations, the receiver 142 mayinclude multiple receivers. The receiver 142 and transmitter 146 receiveand transmit signals, respectively, through an antenna 140. The antenna140 may include separate transmit and receive antennas. In somecircumstances, the antenna 140 may include multiple transmit and receiveantennas.

The transmitter 146 and receiver 142 in the example of FIG. 1B performradio frequency (RF) processing including modulation and demodulation.The receiver 142, therefore, may include components such as low noiseamplifiers (LNAs) and filters. The transmitter 146 may include filtersand amplifiers. Other components may include isolators, matchingcircuits, and other RF components. These components in combination orcooperation with other components perform the signal forwardingfunctions. The required components may depend on the particular signalforwarding scheme that is employed.

The transmitter 146 includes modulator 178 (shown in FIG. 1A), and thereceiver 142 includes demodulator 172 (shown in FIG. 1A). The modulatormodulates the signals to be transmitted as part of the single-encodedforwarded signal 148 and can apply any one of a plurality of modulationorders. The demodulator demodulates the dual-encoded received signal 136in accordance with one of a plurality of modulation orders. Themodulation order for transmissions to the destination device 114,however, is established by scheduler 132.

As is known, the modulation order determines the number of bits used togenerate the modulated symbol. There is a trade-off between modulationorder, required energy, and bit-error rate (BER). As the modulationorder is increased, the average energy per bit must also be increased tomaintain the same BER. In the example shown in FIG. 1B, the signalforwarding device 138 utilizes a lower-order modulation symbol tomodulate the single-encoded data packets before transmitting thesingle-encoded forwarded signal 148. This scenario occurs because atypical link between the signal forwarding device 138 and thedestination device 114 has a relatively lower signal-to-noise ratio(SNR) compared to the link between the origination device 110 and thesignal forwarding device 138. In some situations, for example, theorigination device-to-signal forwarding device (OD-SFD) channel betweenthe origination device 110 and the signal forwarding device 138 istypically static because both devices are fixed, whereas the signalforwarding device-to-destination device (SFD-DD) channel between thesignal forwarding device 138 and the destination device 114 is generallydynamic because the destination device 114 is mobile. Accordingly, theorigination device 110 may utilize a higher-order modulation order whenthe communication link between the origination device 110 and the signalforwarding device 138 is static, which yields a relatively higher SNRcompared to the communication link between the signal forwarding device138 and the destination device 114.

As described above, the signal forwarding device 138 receives thedual-encoded received signal 136 with antenna 140 and receiver 142. Thesignal forwarding device 138 demodulates the dual-encoded receivedsignal 136 with demodulator 172 of FIG. 1A, which yields thedual-encoded data block. The dual-encoded data block is decoded withDecoder 2, 174, of FIG. 1A, which yields a single-encoded data block.

Upon successful decoding by Decoder 2, signal forwarding device 138extracts the first single-encoded data packet from the single-encodeddata block and stores the second single-encoded data packet in a memory(not shown) of the signal forwarding device 138. The firstsingle-encoded data packet is modulated with modulator 178 of FIG. 1A,which yields a single-encoded forwarded signal 148. The signalforwarding device 138 transmits the single-encoded forwarded signal 148via transmitter 146 and antenna 140 to the destination device 114. Inthis manner, the signal forwarding device 138 transmits the firstsingle-encoded data packet, which is contained in the single-encodedforwarded signal 148, to the destination device 114. For the examplesdiscussed herein, the single-encoded forwarded signal 148 is transmittedwithin a single frequency band of the SFD-DD channel. The incomingdual-encoded received signal 136 is transmitted within an originationdevice-to-signal forwarding device channel (OD-SFD channel), which alsoincludes a single frequency band. However, any combination of frequencybands and frequency sub-bands may be used for the OD-SFD channel and theSFD-DD channel.

In some examples, upon receiving the dual-encoded received signal 136,the controller 144 of the signal forwarding device 138 is configured tomeasure the dual-encoded received signal 136 to obtain channelmeasurements associated with the OD-SFD channel between the originationdevice 110 and the signal forwarding device 138. After measuring thedual-encoded received signal 136, the transmitter 146 of the signalforwarding device 138 transmits the OD-SFD channel measurements to theorigination device 110. The OD-SFD channel measurements are transmittedto origination device 110, as indicated by dashed signal line 154 inFIG. 1B. In this manner, the origination device 110, using receiver 118,receives channel feedback regarding the channel conditions associatedwith the communication link between the origination device 110 and thesignal forwarding device 138. Of course, in other examples, theorigination device 110 can also obtain its own channel measurementsregarding the channel conditions associated with the communication linkbetween the origination device 110 and the signal forwarding device 138by measuring incoming signals from the signal forwarding device 138.After receiving the channel feedback, controller 120 of originationdevice 110 can modify the set of encoding parameters used by Encoder 2,168, based on the received channel feedback regarding the channelconditions associated with the communication link between theorigination device 110 and the signal forwarding device 138.

The destination device 114 receives the single-encoded forwarded signal148 via antenna 124 and receiver 130. The destination device 114 furthercomprises controller 128 and transmitter 126, as well as otherelectronics, hardware, and code. The destination device 114 is anyfixed, mobile, or portable equipment that performs the functionsdescribed herein. The various functions and operations of the blocksdescribed with reference to the destination device 114 may beimplemented in any number of devices, circuits, or elements. Two or moreof the functional blocks may be integrated in a single device, and thefunctions described as performed in any single device may be implementedover several devices.

The controller 128 includes any combination of hardware, software,and/or firmware for executing the functions described herein as well asfacilitating the overall functionality of the destination device 114. Anexample of a suitable controller 128 includes code running on amicroprocessor or processor arrangement connected to memory. Thetransmitter 126 includes electronics configured to transmit wirelesssignals. In some situations, the transmitter 126 may include multipletransmitters. The receiver 130 includes electronics configured toreceive wireless signals. In some situations, the receiver 130 mayinclude multiple receivers. The receiver 130 and transmitter 126 receiveand transmit signals, respectively, through an antenna 124. The antenna124 may include separate transmit and receive antennas. In somecircumstances, the antenna 124 may include multiple transmit and receiveantennas.

The transmitter 126 and receiver 130 in the example of FIG. 1B performradio frequency (RF) processing including modulation and demodulation.The receiver 130, therefore, may include components such as low noiseamplifiers (LNAs) and filters. The transmitter 126 may include filtersand amplifiers. Other components may include isolators, matchingcircuits, and other RF components. These components in combination orcooperation with other components perform the destination devicefunctions. The required components may depend on the particularfunctionality required by the destination device.

The transmitter 126 includes a modulator (not shown), and the receiver130 includes demodulator 180 (shown in FIG. 1A). The modulator modulatesthe signals to be transmitted as part of the channel measurement signals150, 152 and can apply any one of a plurality of modulation orders. Thedemodulator demodulates the single-encoded forwarded signal 148 inaccordance with one of a plurality of modulation orders.

As described above, the destination device 114 receives thesingle-encoded forwarded signal 148 with antenna 124 and receiver 130.The destination device 114 demodulates the single-encoded forwardedsignal 148 with demodulator 180 of FIG. 1A, which yields the firstsingle-encoded data packet. The first single-encoded data packet isdecoded with Decoder 1, 182, of FIG. 1A, which yields the user data(e.g., received user data 186).

In some examples, upon receiving the single-encoded forwarded signal148, the controller 128 of the destination device 114 is configured tomeasure the single-encoded forwarded signal 148 to obtain channelmeasurements associated with a signal forwarding device-to-destinationdevice (SFD-DD) channel between the signal forwarding device 138 and thedestination device 114. After measuring the single-encoded forwardedsignal 148, the transmitter 126 of destination device 114 transmits theSFD-DD channel measurements to the origination device 110. The SFD-DDchannel measurements can be transmitted directly to origination device110, as indicated by dashed signal line 150 in FIG. 1B. Alternatively,the SFD-DD channel measurements can be initially transmitted to signalforwarding device 138, as indicated by dashed signal line 152, andsignal forwarding device 138 can subsequently transmit the SFD-DDchannel measurements to origination device 110, as indicated by dashedsignal line 154. Of course, in other examples, the signal forwardingdevice 138 can also obtain its own channel measurements regarding thechannel conditions associated with the communication link between thesignal forwarding device 138 and the destination device 114 by measuringincoming signals from the destination device 114. The signal forwardingdevice 138 may then transmit its own channel measurements to theorigination device 110. Thus, there are multiple ways in which theorigination device 110, using receiver 118, can receive channel feedbackregarding the channel conditions associated with the communication linkbetween the signal forwarding device 138 and the destination device 114.After receiving the channel feedback, controller 120 of originationdevice 110 can modify the set of encoding parameters used by Encoder 1,164, based on the received channel feedback regarding the channelconditions associated with the communication link between the signalforwarding device 138 and the destination device 114.

In some examples, destination device 114 can also transmit the SFD-DDchannel measurements to origination device 110, either directly orindirectly through signal forwarding device 138, as part of a feedbacksignal. Alternatively, the SFD-DD channel measurements can betransmitted separately from the feedback signal. For example, thefeedback signal can include a downlink channel feedback reportcomprising downlink channel measurements related to one or more downlinksignals received by the destination device 114. For example, thedownlink channel feedback report may contain downlink channelmeasurements for downlink signals received from the origination device110 and/or downlink channel measurements for one or more downlinksignals received from one or more base stations other than originationdevice 110. The downlink channel feedback report can additionallyinclude the location of the resources (e.g., time slots, subcarriers,reference signal, etc.) on which the downlink channel measurements weremade.

The downlink channel feedback report may also identify a carrier onwhich the downlink channel measurements were made, a cell identifierassociated with origination device 110 that transmitted the downlinksignals, and/or a spatial vector associated with a beamformed downlinksignal. In some examples, the downlink channel feedback report mayidentify a cell identifier associated with a base station, other thanorigination device 110, that transmitted the downlink signal. Thisscenario might occur when the downlink signal is received from a basestation other than origination device 110, but the destination device114 needs to submit the downlink channel feedback report to thescheduler 132 located at the origination device 110.

In yet another scenario, destination device 114 can receive downlinksignals from a first device (e.g., origination device 110), as theprimary carrier of the downlink signals, and can also receive downlinksignals from a second device (e.g., signal forwarding device 138 or abase station other than origination device 110), as the secondarycarrier of the downlink signals. In such a scenario, the downlinkchannel feedback report may (1) identify the primary carrier and/or thesecondary carrier on which the downlink channel measurements were made,(2) include a cell identifier associated with the first device thattransmitted the primary carrier and/or a cell identifier associated withthe second device that transmitted the secondary carrier, and/or (3)include a spatial vector associated with each of one or more beamformeddownlink signals, respectively.

Alternatively, the feedback signal can include an acknowledgmentresponse, which can be either a positive acknowledgment response (ACK)or a negative acknowledgment response (NACK). The ACK message indicatesthat a downlink signal was successfully received by the destinationdevice 114. The NACK message indicates that the downlink signal was notsuccessfully received by the destination device 114. In some situations,the ACK/NACK message is a message that is forwarded on to theorigination device 110 by the signal forwarding device 138. In othersituations, it a message intended for the signal forwarding device 138.In still other situations, the ACK message can be an indication to boththe signal forwarding device 138 and the origination device 110. Inscenarios in which the feedback signal includes an acknowledgmentresponse, the feedback signal may additionally identify a carrier onwhich the downlink signal was received, a cell identifier associatedwith origination device 110 that transmitted the downlink signal, a cellidentifier associated with a base station, other than origination device110, that transmitted the downlink signal, and/or a spatial vectorassociated with a beamformed downlink signal. Regardless of the contentsof the feedback signal, the SFD-DD channel measurements can betransmitted along with, or separate from, the feedback signal to theorigination device 110, either directly or through signal forwardingdevice 138.

FIG. 2 is a flowchart of an example of a method 200 of utilizing thewireless communication system of FIG. 1B to transmit dual-encoded data.The method begins, at step 202, with encoding a first data packet and asecond data packet according to a first set of encoding parameters. Asdescribed above, the first set of encoding parameters corresponds tochannel conditions associated with a first communication link betweenthe signal forwarding device 138 and the destination device 114. Thefirst set of encoding parameters may include a first encoding techniqueand/or a first encoding rate. The result of step 202 is first and secondsingle-encoded data packets.

At step 204, the first and second single-encoded data packets arecombined to generate a single-encoded data block. At step 206, thesingle-encoded data block is encoded according to a second set ofencoding parameters. The second set of encoding parameters correspondsto channel conditions associated with a second communication linkbetween the origination device 110 and the signal forwarding device 138.The second set of encoding parameters may include a second encodingtechnique and/or a second encoding rate. The result of step 206 is adual-encoded data block.

At step 208, the origination device 110 transmits a dual-encodedreceived signal 136, which contains the dual-encoded data block, to thesignal forwarding device 138. At step 210, the signal forwarding device138 decodes the dual-encoded data block, using decoding parameters thatcorrespond to the second set of encoding parameters, to obtain the firstand second single-encoded data packets that are encoded according to thefirst set of encoding parameters. At step 212, the signal forwardingdevice 138 transmits a single-encoded forwarded signal 148, whichcontains the first single-encoded data packet, to destination device114. The signal forwarding device 138 can also measure the dual-encodedreceived signal 136 to obtain channel measurements associated with thecommunication link between the origination device 110 and the signalforwarding device 138.

The destination device 114 receives and attempts to decode the firstsingle-encoded data packet, using decoding parameters that correspond tothe first set of encoding parameters. If the decoding procedure issuccessful, the destination device 114 will have successfully receivedthe user data. If the decoding procedure is unsuccessful, thedestination device 114 will transmit a NACK to the signal forwardingdevice 138.

At step 214, the signal forwarding device 138 receives a request forretransmission (e.g., NACK), indicating that the first single-encodeddata packet was not successfully received by the destination device 114.At step 216, the signal forwarding device 138 transmits the secondsingle-encoded data packet to the destination device 114, in response tothe received request for retransmission (e.g., NACK that was transmittedin response to the unsuccessful attempt to decode the firstsingle-encoded data packet).

In this regard, if system 100 of FIG. 1B utilizes a Hybrid AutomaticRepeat Request (HARQ) process for error-correction and error-control,each ACK/NACK transmitted from the signal forwarding device 138 and thedestination device 114 may include an identifier in order to identifythe device that initially transmitted the ACK/NACK. In some cases, theHARQ Process ID may also be used. When using the HARQ mechanism, thereceiver and the transmitter should know some information about theProcess ID for each of the HARQ processes, so that the receiver cansuccessfully track each of the HARQ process data without getting themmixed up. In this case the HARQ process ID could be included along withthe identifier for the identity of the device.

Clearly, other embodiments and modifications of this invention willoccur readily to those of ordinary skill in the art in view of theseteachings. The above description is illustrative and not restrictive.This invention is to be limited only by the following claims, whichinclude all such embodiments and modifications when viewed inconjunction with the above specification and accompanying drawings. Thescope of the invention should, therefore, be determined not withreference to the above description, but instead should be determinedwith reference to the appended claims along with their full scope ofequivalents.

1. A method comprising: encoding a first data packet and a second datapacket, according to a first set of encoding parameters corresponding tochannel conditions associated with a first communication link between asignal forwarding device and a destination device, to generate first andsecond single-encoded data packets, wherein the first and secondsingle-encoded data packets contain redundant encoded data; and encodingthe first and second single-encoded data packets, according to a secondset of encoding parameters corresponding to channel conditionsassociated with a second communication link between an originationdevice and the signal forwarding device, to generate a dual-encoded datablock.
 2. The method of claim 1, wherein the first set of encodingparameters comprises a first encoding technique, and wherein the secondset of encoding parameters comprises a second encoding technique.
 3. Themethod of claim 1, wherein the first set of encoding parameterscomprises a first encoding rate, and wherein the second set of encodingparameters comprises a second encoding rate.
 4. The method of claim 1,further comprising: transmitting the dual-encoded data block to thesignal forwarding device.
 5. The method of claim 4, further comprising:receiving channel feedback regarding the channel conditions associatedwith the first communication link between the signal forwarding deviceand the destination device.
 6. The method of claim 5, furthercomprising: modifying the first set of encoding parameters based on thereceived channel feedback regarding the channel conditions associatedwith the first communication link between the signal forwarding deviceand the destination device.
 7. The method of claim 4, furthercomprising: receiving channel feedback regarding the channel conditionsassociated with the second communication link between the originationdevice and the signal forwarding device.
 8. The method of claim 7,further comprising: modifying the second set of encoding parametersbased on the received channel feedback regarding the channel conditionsassociated with the second communication link between the originationdevice and the signal forwarding device.
 9. The method of claim 4,further comprising: receiving the dual-encoded data block at the signalforwarding device; decoding, by the signal forwarding device, thedual-encoded data block, using decoding parameters that correspond tothe second set of encoding parameters, which yields the first and secondsingle-encoded data packets that are encoded according to the first setof encoding parameters; and transmitting, by the signal forwardingdevice, the first single-encoded data packet to the destination device.10. The method of claim 9, further comprising: receiving, at the signalforwarding device, a request for retransmission of the firstsingle-encoded data packet; and transmitting, by the signal forwardingdevice, the second single-encoded data packet to the destination device,in response to the request for retransmission.
 11. The method of claim1, further comprising: combining the first and second single-encodeddata packets to generate a single-encoded data block before encodingaccording to the second set of encoding parameters to generate thedual-encoded data block.
 12. A wireless communication system comprising:an origination device comprising: circuitry configured to: encode afirst data packet and a second data packet, according to a first set ofencoding parameters corresponding to channel conditions associated witha first communication link between a signal forwarding device and adestination device, to generate first and second single-encoded datapackets, wherein the first and second single-encoded data packetscontain redundant encoded data, and encode the first and secondsingle-encoded data packets, according to a second set of encodingparameters corresponding to channel conditions associated with a secondcommunication link between the origination device and the signalforwarding device, to generate a dual-encoded data block, and atransmitter configured to transmit the dual-encoded data block; a signalforwarding device comprising: a receiver configured to receive thedual-encoded data block, circuitry configured to decode the dual-encodeddata block, using decoding parameters that correspond to the second setof encoding parameters, which yields the first and second single-encodeddata packets that are encoded according to the first set of encodingparameters, and a transmitter configured to transmit the firstsingle-encoded data packet to the destination device; and a destinationdevice comprising: a receiver configured to receive the firstsingle-encoded data packet, and circuitry configured to decode, usingdecoding parameters that correspond to the first set of encodingparameters, the first single-encoded data packet.
 13. The wirelesscommunication system of claim 12, wherein the first set of encodingparameters comprises a first encoding technique, and wherein the secondset of encoding parameters comprises a second encoding technique. 14.The wireless communication system of claim 12, wherein the first set ofencoding parameters comprises a first encoding rate, and wherein thesecond set of encoding parameters comprises a second encoding rate. 15.The wireless communication system of claim 12, wherein the originationdevice further comprises: a receiver configured to receive channelfeedback regarding the channel conditions associated with at least oneof the first communication link and the second communication link. 16.The wireless communication system of claim 15, wherein the originationdevice further comprises: a controller configured to modify at least oneof the first set of encoding parameters and the second set of encodingparameters, based on the received channel feedback.
 17. The wirelesscommunication system of claim 12, wherein the destination device furthercomprises: a transmitter configured to transmit, to the signalforwarding device, a request for retransmission of the firstsingle-encoded data packet, if the destination device is unable todecode the first single-encoded data packet.
 18. The wirelesscommunication system of claim 17, wherein the transmitter of the signalforwarding device is further configured to transmit the secondsingle-encoded data packet to the destination device, in response to therequest for retransmission.
 19. The wireless communication system ofclaim 12, wherein the circuitry of the origination device is furtherconfigured to combine the first and second single-encoded data packetsto generate a single-encoded data block before encoding according to thesecond set of encoding parameters to generate the dual-encoded datablock.